/**
 *  Copyright (c) 1997-2013, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.tinysqldsl.expression.relational;

import org.tinygroup.tinysqldsl.base.Condition;
import org.tinygroup.tinysqldsl.base.StatementSqlBuilder;
import org.tinygroup.tinysqldsl.expression.Expression;

public class ExistsExpression implements Expression {

	private Expression rightExpression;
	private boolean not = false;

	public ExistsExpression(Expression rightExpression) {
		this(rightExpression, false);
	}

	public ExistsExpression(Expression rightExpression, boolean not) {
		super();
		this.rightExpression = rightExpression;
		this.not = not;
	}

	public static Condition existsCondition(Expression rightExpression,
			Object... values) {
		return new Condition(new ExistsExpression(rightExpression), values);
	}
	
	public static Condition notExistsCondition(Expression rightExpression,
			Object... values) {
		return new Condition(new ExistsExpression(rightExpression,true), values);
	}

	public Expression getRightExpression() {
		return rightExpression;
	}

	public boolean isNot() {
		return not;
	}

	public String getStringExpression() {
		return ((not) ? "NOT " : "") + "EXISTS";
	}

	public String toString() {
		return getStringExpression() + " " + rightExpression.toString();
	}

	public void builderExpression(StatementSqlBuilder builder) {
		StringBuilder buffer = builder.getStringBuilder();
		if (isNot()) {
			buffer.append("NOT EXISTS ");
		} else {
			buffer.append("EXISTS ");
		}
		getRightExpression().builderExpression(builder);
	}
}
